The present invention relates to apparatus for pumping air to a submerged diver.
Many types of apparatus have been designed to allow a swimmer to breathe underwater. The simplest, a snorkel, is simply a tube which extends from the swimmer's mouth to the surface. The disadvantage of the snorkel is that a swimmer would have to hold his breath to go any deeper than the surface of the water. Extended snorkels, with the upper end supported by a float on the surface of the water, have been tried. However, as the diver gets deeper and the water pressure gets higher, the tube becomes of less and less use. Finally, at a relatively shallow depth, the diver can no longer breathe through the tube.
Perhaps the earliest method of supplying air for a diver to breathe underwater is to have a pump located above the water's surface on a boat or dock. Air is then supplied through a hose and may simply be fed into a pressurized suit worn by such divers for deep sea diving. While this allowed extended diving, the heavy suits and thick tubing required did not permit free diving, and required a crew on the surface to tend the compressor (and, in the earliest versions, to actually operate the pump by hand).
The limitations of the "hard hat" diving suit were largely allieviated by the "SCUBA" (Self-Contained Underwater Breathing Apparatus) developed by Jacques Cousteau in the early 1950's (see Cousteau, U.S. Pat. No. 2,593,988). A pressurized tank of air is worn by the diver on his back. The air pressure is regulated according to the demand and depth and is supplied to the diver through a hose and mouthpiece. The diver can swim freely and breathe at depths below the surface with tank pressure sufficient to compensate for water pressure at a particular depth. However, there is extensive training required for such a device, and the time underwater is strictly limited by the capacity of the air tanks.
In an attempt to combine the advantages of SCUBA and surface-supply systems, while maintaining the ability to swim more-or-less freely, a number of products have been developed which float independently on the surface of the water and pump air to a submerged swimmer. Typically such a device consists of an air compressor powered by a gasoline engine mounted on a floatation device such as a large inner tube or raft. The diver is supplied with air through a float tube. Such a device is currently being sold by Keene Engineering of Northridge, Calif. (see page 27, "Model 263GH Mounted on a Tote Float", Spring 1993 catalog).
Although the air supply can be isolated from the engine to some degree, there are risks of contamination of the air from exhaust of the gasoline engine. To avoid this risk, some inventors have used electric motors to power the compressor. For example, see Taylor, U.S. Pat. No. 3,400,680. The present inventor has previously invented and sold a solar-powered floating air compressor system, which was the subject of U.S. patent application No. 06/804,444, filed Dec. 4, 1985, now abandoned.
Electrically powered compressors are cleaner but they produce an electrical arc at the armature of their motor. This arc is potentially dangerous and gases including hydrogen from the battery can cause safety problems. Mitchell, U.S. Pat. No. 4,674,693 is an example of a floating compressor in which the battery and motor are enclosed in a sealed compartment, which would present the risk of ignition of the battery outgassing by any sparks from the motor.
As with the examples cited above, all of the electric-compressor diving devices known to the inventor are designed using one compressor, which leaves no back up air supply in case of mechanical failure.
In addition, the battery life of electric compressors is limited by the fact that the compressor in all prior art devices runs continuously.
Also, although various devices have used various schemes for avoiding water intake into the compressor (such as the snorkel used by Mitchell), such methods have met with limited success. The spray and wave action common in most open water situations lead to water ingestion in any system using open air intakes.
There is a need for a small, floating, electrically powered diving device that is clean, mechanically and chemically safe, with an automatic on demand air supply to conserve battery power while the diver is not breathing.